Highlights

Hazardous waste materials on five abandoned mines posed serious risks to humans and the environment.

Mining contaminants were polluting area surface and groundwater, and potentially impacting water supplies downstream.

The contaminants were dangerous to campers and area residents, and threatened aquatic life.

Following a detailed sampling process, BLM removed the metals and restored the water’s pH levels.

Federal Agency Landowner

Bureau of Land Management

The La Sal Creek Watershed Project covers the final three- to four-mile stretch of La Sal Creek as it leaves Utah and enters Colorado. Mining in the area dates back to the 1950s, when drilling programs conducted by the USGS discovered uranium and vanadium in a zone that became known as the “La Sal Creek Mineral Belt.” To reach these deposits, horizontal passageways were bored through the rock, creating piles of waste materials that remain on each of the area’s five mines (now abandoned). These abandoned mine sites are located along the northern rim of the canyon formed by La Sal Creek, a perennial stream that drains the southern flank of the La Sal Mountains. Three permanent residences currently reside within the project area beneath the Firefly/Pygmy Mine (approximately one percent of the dump area) on national forest system lands. The other four mines that were part of this project were: Black Hat, Blue Cap, and St. Patrick mines. They are located immediately below the sandstone rim of Lion Canyon. Water quality samples confirmed that mining contaminants—including arsenic and radioactive materials—were leaching from waste rock piles, polluting area surface and groundwater, and potentially impacting water supplies downstream. These contaminants presented a risk to campers as well as area residents, and threatened aquatic life within both La Sal and nearby Lion Canyon Creek.

Starting with detailed water, pasture, and sediment sampling in 2000 and 2001, the BLM began a series of steps to address and correct the problems caused by the region’s mining legacy. The Bureau finalized a safety and health plan in December 2002, a conceptual site model in June 2003, a field sampling plan in January 2004, and an engineering evaluation/cost analysis (EE/CA) in October 2005. Resulting actions, started in the summer of 2010, included constructing a sulfate-reducing bioreactor to remove metals and restore the proper pH of ground and surface water; sealing mine adits; demolition and disposing of unsafe structures; removing lower-level radiation debris; stabilizing slopes; and planting vegetation to absorb further contamination. Ongoing monitoring and maintenance will ensure that these remedies are functioning as designed and protecting human health and the environment.